Jaco P Bloem

Just some feedback on this topic.  Five months after upgrading to 71.82, I again experienced the high charge voltage issue.  Have now upgraded to 71.92.  Touch wood........

Great, thanks! Yes I will assist with the cable, laptop and software with instructions (from the Topic feed given earlier)..

@Coulomb Thank you for the reply, is there any software for this type of inverter maybe?
I have it running with a Dyness 4.8kw/h battery and don't want to damage this battery seeing that it's quite expensive 😅

Hi, yes I will gladly assist..
I have an old laptop I use with a series port and the Axpert cable. We just need to be very careful to use the correct Firmware file, if you can source the latest file for your inverter (always best to ask your supplier or the specialist in this Forum if you do not have the new firmware).  You can email me privately so we can discuss 🙂
Kind Regards 
Jaco 

..one thing I do not have is good monitoring software! Are you using ICC on the Raspberry Pi?
My first installation (2019) is 12 x 330W Canadian Solars, the array is two parallel strings of 6 in serie each.
I have now added the second inverter with 8 x 360W Panel array all in serie to the second inverter - running in parallel with the first Axpert.
Hats of to the mppt chargers referencing different input voltages (223V DC on the one and 317V on the other), and still maintaining equal power drawn. When the load exceeds the capability of one of the PV arrays, then only will the first array ( my old set) supply more than the other - to a point where both give max for the time of day.. 
Just by watching the Displays and WatchPower I do not see major fluctuations (227 to 233 Vac which is 1.3%) but I will have to record the Voltages to see if I have a similar drop - that you and others have noticed.
It's difficult to comment on your graphs as one must compare them with the Voltages and also I am sure you have Battery usage and charging as well (?). 
Thanks for sharing! 
((PS: I see a 10% PV power increase in my old array each time I wash the panels - it's dusty in Bloem! 😅))
Jaco P

Hi Guys so here is another GIVE AWAY!
 
We are busy with a test and review of the GREENRICH U-P5000 1.5C 4.96 kWh Lithium Battery 
 
Yes we will be giving one away to one lucky Power Forum Member in a Lucky Draw 
 
I will post details on how to qualify for this GIVE AWAY soon watch this space!
 
Sponsored by Elleyhill Power (PTY) LTD
 
So some educational information about these batteries 
 
As you all know Greenrich batteries have been in the market for some time now and so far we have had mostly positive feedback from installer and end users alike.
 
What makes the battery desirable is the 1.5C Rating this means the battery can discharge at 1.5 times its capacity rating.
 
Why would that be so great?
 
Here is why if you have a 8KW inverter discharge the battery at 8kWh then this 4.96 kWh battery will be able to absorb a charge rate between 0.5C & 0.75C and a discharge rate at 1.5C without tripping the benefits of that is that when you start of on your solar journey you don't have to break the bank with just one 4.96 kWh Greenrich Battery because your 8KW inverter will struggle to reach the discharge rates of the battery. 
 
The 4.96 kWh is also inter compatible with the 3.686 kWh Greenrich Lithium if you require to expand to additional capacity.
 
This Lithium battery is the only Lithium battery in the market that offers true 1.5C discharge ratings. With 1.5C discharge rates, the Greenrich lithium battery has a much higher power output compared to other 0.5C or 1C lithium batteries. 
 
The cell technology in the battery is LFP cylindrical high density cells which can do up to 2C however for longevity the BMS limits the discharge  to 1.5C and charger rates to 0.5C continuous and boost charge rate for 5 minutes to 0.75C
Features:
High density energy
Long Life span
(10 years life performance warranty, >6000cycles)
More Capacity possibility (15 in parallel)
Quick Charging and discharging
Overvoltage protection；
Undervoltage protection;
Short-circuit protection;
Low temperature charge protection；
High temperature charge protection；
Low temperature discharge protection；
High temperature discharge protection;
Charge over-current protection;
Discharge over-current protection;
Dormancy function;
RS485 communication;
CAN communication.
RS232 communication
Compatibility tested with many inverters
Sunsynk
Deye
Growatt
Voltronic
Kodak
EV Tech being used for Energy storage
Relationship between CAPACITY and POWER
USABLE capacity
Safety
Compatibility
Application environment
UP5000 16S21P= 336 Cells (46000mAh per cell)
Battery specifications:
Weight: 51 kg
Dimensions:        55 × 47 × 30 cm
Battery Type: Lithium Ion
Nominal Energy: 4960 Wh
Depth of discharge: 95.00 %
Voltage: 51.2v
Normal Discharging Temperature Greenrich.-10°C to 60°C.   
Others Batteries 45°C max
Normal Charging Temperature 0°C to 50°C
Continuous Discharge Rate (Normal Use): 7 680 W
Surge Discharge Rate (100 Milli Seconds): 17 920 W
Maximum Charge Rate (5 Minutes): 4 096 W
Compatible with many of South Africa’s popular Hybrid inverters’ brands.
Built-in BMS that protects the cell from abnormal temperature, current, voltage, SoC, and SoH.
DATA SHEET

We will make a post here with all the details and requirements to qualify for the Lucky Draw.

Hi Jaco. 
 
It could be many issues. One being that the EL is too sensitive. If the inverter is being fed through the EL, it will trip. The E/N bondind is only required on the LOAD/Essential side of the inverter when the grid fails. So when the grid is down, you need to bond Earth and the LOAD neutral. 
 
If this isn’t done then there will be approx 110V between Earth and Neutral on the LOAD side which isn’t legal. 

It may be that one of the battery modules is out of balance with the other. Check the voltage of each 12V module to see if they have a nearly identical voltage, within about 0.1V. If  not, charge the lower voltage module with a car battery charger, until the voltage (after resting at least a few minutes, preferably half an hour) is about the same. 

Got the sign-off from CoCT about a month ago, so my DIY solar project is finally done and dusted. Thanks to everyone on the forum that provided advice - I probably would have stuffed it up if it wasn't for you.
The whole project took about three months of evenings and weekends to finish, and was a welcome distraction from the current state of the world.
 

4 strings of 4 Canadian Solar 400Wp poly panels in series, facing NNE.
 

Another string of 4 Canadian Solar 400Wp panels in series, facing WNW.
All five strings are paralleled together for a combined 8kWp.
 

This is my main DB. CoCT installed a new split prepaid meter. According to the technician that installed it it has built-in reverse power blocking. I have tested it to see what it does when I try to feed in power in to the grid, and it charges me in both directions. That is perfectly fine in my opinion - much preferable to it tripping when there is momentary feed-in.
Grid power is measured by an ET112. There is a breaker that connects the main DB to the solar installation in the scullery:

Top-left is the AC DB. Top-right is the DC combiner box. Bottom left is the Multiplus II 5kVA inverter, and bottom middle the SmartSolar 250/100 MPPT. The SmartSolar was initially running a bit hot for my liking, so I mounted it on a 6mm thick aluminium plate which brought down peak temperatures from 82C to 65C. Bottom-right is the Victron Cerbo. The battery cabinet on the floor contains 5 PylonTech US2000 batteries for a total nominal capacity of 12kWh. I've set it to 80% DoD:
 
 

Close-up of the DC buses.
 

Close-up of the AC DB, with and without cover.
 


Close-up of the DC combiner box, with and without cover.
The geyser and oven, as well as the swimming pool DB are connected to the main DB, so those are unpowered when there is loadshedding. The AC DB in the scullery is connected to the output of the Multiplus, so all the essential loads stay powered when grid power goes down.
 

Thank you so much I have changed the settings and the system is working no more errors, switching over to Solar automatically.
We are so happy to see it working automatically.
Thank you to everyone that assisted me. I have gained alot of knowledge on how this works.
We plan on expanding by adding more solar panels hopefully by next month. 

Hi 
Do you perhaps have more information on the battery? If it is a 15 cell Life battery, the charge Voltage might be too high.
I can propose the following :
Bulk Charge : 52.5V
Float : 51.8V
Also setting 12 should be 48V then the battery will not drain completely (if this is your 'point back to Utility' setting?
Setting 13 to 51 V (back to battery)
If you can give this a try? It may be that the battery BMS protects itself from the high voltage (as 54V sounds more like flooded battery settings).
Let us know 
Kind Regards 
Jaco P

Hi Erwin
I do not have knowledge of the Growatt inverters, but have two Mecer Axperts in parallel. You are correct in that all similar AC in/out puts and Battery DC are parallel connected on the two inverters, except the PV inputs.
You may not bridge the PV inputs as then you effectively parallel the 2 DC input sources (that you have designed with care in your drawing 😉) and short-circuiting the two mppt chargers.
I am sure it will be similar with the Growatt: on the Axperts you connect a ton of communication and current sharing cables (a parallel communication kit) .. in order for the inverters to cleverly balance the power drawn from the 2 different PV sources, battery charging and AC (load) output..  (Perhaps check with the supplier?)
Kind Regards
Jaco P

It's a series string and the total length is that of the complete string. The length of the positive wire vs. the negative one does not impact that. 
A 4 mm2 wire has a rating of 48A. Your panels are in series so that should be fine as well.
For the loss over the 16m distance though, you might be better off using 6 mm2, but the 4 mm2 will work just fine ( 0.4V loss more for the 4 mm2 )

I've flashed my 2x Axpert MKS II inverters with the latest firmware (71.82).  I've attached the firmware to this post for interest sake.  Whatever you do with it is at your own risk.
I used this cable and it worked the first time on both. Note this cable goes from your computer to the serial cable that came with the inverter (see picture):
https://www.takealot.com/ce-link-usb-2-0-to-rs232-db9-serial-male-a-2m-cable/PLID51855970
The inverters remained connected via parallel cable during upgrade.  I turned one on and the other off, which sets the one turned on to master.  I then flashed the master.  Did the same to the other one.  Note sure if this process made any difference I'm just posting it anyway.
Mostly followed the instructions from @Coulomb from this link. Didn't reset all settings with watchpower afterwards. Note files on this link should NOT be used with MKS II, the instruction is just the same: https://forums.aeva.asn.au/viewtopic.php?title=pip4048ms-inverter&p=64096&t=4332#p64096
Note it seems like the MKS II doesn't have SCC firmware to upgrade.  On the inverter display I can see the inverter version (U1) but scrolling up or down doesn't show a SCC version (U2).
 


MKS II Firmware 71 82.zip

I still want to do an experiment with that and perhaps turn it into a video. I want to add 14D431K MOVs until the RCD trips. I also want to test and demonstrate what happens when the TN bond is temporarily disconnected and reconnected, as is done by inverters when they do their relay test.

From a binary code perspective, the differences from 71.80 to 71.82 appear to be:
1) In SolarVolt1Chk(), the "tolerance" for PV low loss and return are multiplied by 10. That means in effect that instead of needing to see a deviation for 5 calls in a row (0.1 seconds) with no exceptions, it now wants to see 50 calls in a row with no exceptions (1 second). My guess is that this is the change in 71.81.
2) In FaultMode(), there is a new case to a large switch statement; servicing fault code 11 (PV over volts). In this case, new code sets bRestartFlag (making the fault restartable), if GetBusOverCount() < 3 and also _g_uwSolar1HighLoss is false. This seems to allow some PV over-voltage events to no longer be "fatal" faults; after 10 seconds, it's possible to exit fault mode and continue operation, unless it was a "bad" overvoltage.
3) There is extra code in FaultMode() [ edit: just before the main loop in FaultMode() ] to count a fault code 11 [ edit: in addition to fault code 08, as before ] as a bus-over-voltage (i.e. GetBusOverCount() will return 1 more).
I have to dash to an appointment now; I just wanted to get this down before I forget it.

Hi, I'm running two parallel Growatt inverters. Like @Jaco P Bloem say, do not parallel the PV inputs, every other inputs and outputs are paralleled as per the installation manual except the PV inputs. In my case, I have four panels, 405W JA Solar with Voc of 49.86v. I have connected two panels in series and then wired them to 1st inverter and then connected the other two and wired to the 2nd inverter. Do not forget to connect isolators between your inverters and solar panels. I'm planning to add four more at the end of the month so that I can have 8. 

Dankie vir die reply Jaco -daar leer ek nog. 

Hi Jannie
I have a similar setup, with the same 2 Axperts in parallel but only 20 panels (12 x 330W on the one and 8 x 360W on the other).
You can install your first set (array) as 7s+7s to the one inverter and the second set as 8s+8s to the second inverter. Then all 30 panels are utilised.
{This is, you parallel two series strings of 7 panels in set 1} 
The 2 sets do not have to be identical as they each go to their own MPPT charger, as long as the parallel strings are equal and you stay below the 450V.
The operating Voltage is lower than the stated Voc (Open Circuit V), so you may see a Voltage of less than 300V dc on the inverter for set 2.
The current source in both sets will then be 18Amp (max operating I).
Let us know please how it goes!
(you will notice how clever the Parallel configuration will utilise the power drawn from the 2 uneven PV sets)
Kind Regards
Jaco
PS: I did enquire my supplier in the past and Voltronic replied to say it is safe to over-design the PV by 20% that is 5400W (max!) on one inverter, however the Inverter will not draw more than 4500. You should be OK with 16 panels (4800W) in the second set..

So now let me get into the HF vs LF design difference.
Low Frequency designs work like this. You take your 48VDC, and you convert it to 48VAC at 50Hz (a little bit less really, there's some losses in this part). Then you feed this 50Hz low voltage into a big old conventional transformer and on the other side pops out 230VAC. The transformer needs to be big, because the time period t = 1/f is relatively long when f = 50Hz, so you need a nice big store of magnetic energy.
A high frequency design works similar, but it has an extra stage at the end. You again start with your 48VDC, and convert it to 48VAC... but at a MUCH higher frequency (typically 40Khz and above). This also doesn't have to be a sine wave. You then feed this into a transformer again, and convert it to a higher voltage, and then you rectify it back to DC, so that you end up with around 350VDC. This is the so-called high-voltage DC bus that we sometimes talk about, and there is a reason why it needs to be higher than the expected 230V.
You then have a final stage that takes this 350VDC and switches/slices it into a sine wave, and voila, you have 230VAC (RMS).
Because your frequency is much higher, the time constant t = 1 / f is much smaller, and hence a smaller magnetic store is needed.
Also, why 350VDC? Because the 230VAC we are used to is actually an average, an "RMS" value. It's the equivalent DC voltage if you will. Visually, you could think of taking the peaks of the sine wave, slicing them off, and dumping them into the valleys, and it will then level out at 230VDC. The peaks of the sine wave is actually around 325V... and this is why the high voltage DC bus must be at a higher voltage.
OK kids... class dismissed. If I got something wrong, there will be a teacher along to correct me shortly 🙂
 

I reckon this subject is still not resolved. Ideally the geyser should be connected as a non essential load (so if there is enough PV power available it will switch on the geyser element) What type of system you have also has to be considered..
Have a look at this thread on another forum (especially Gerlagh's comments) https://www.4x4community.co.za/forum/showthread.php/330544-Solar-geyser-backup-element-usage

I believe anything is possible if you put your mind to it.
If you have a Pi running ICC you can definitely do it. Mannie has developed an app called APM which gets values from ICC see below, so you wire the geyser with 1 x 2CH sonoff swicth with 2 x relays 30amp (1 to grid AC and the other to inverter AC) and do the automation on APM. Done.